USPTO Patents Application 10687850

per

WORLD INTELLECTUAL PROPERTY ORGANIZATION
International Bureau

INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(51) International Patent Classification 3 :
G01N 21/01, 21/27; G01J 3/46

Al

(11) International Publication Number: WO 83/ 00926

(43) International Publication Date: 17 March 1983 (17.03.S3)

(21) International Application Number: PCT/AU82/00141

(22) International Filing Date: 26 August 1982 (26.08.82)

(31) Priority Application Number: PF 0477

(32) Priority Date: 28 August 1981 (28.08.81)

(33) Priority Country: AU

(71) Applicant (for all designated States except US): LIGG

PTY. LIMITED [AU/AU]; 21 Mooramba Road, Dee
Why, N.S.W. 2099 (AU).

(72) Inventor; and

(75) Inventor/Applicant (for US only) : CLARK, Stanley
[GB/AU]; 21 Mooramba Road, Dee Why, RS.W.
2099 (AU).

(74) Agent: SPRUSON & FERGUSON; GJP.O. Box 3898,
Sydney, N.S.W. 2001 (AU).

(81) Designated States: AT (European patent), AU, BE (Eu-
ropean patent), BR, CH (European patent), DE (Eu-
ropean patent), DK, FR (European patent), GB (Eu-
ropean patent), JP, LU (European patent), NL (Euro-
pean patent), NO, SE (European patent), SU, US.

Published

With international search report.

(54) Title: REFLECTANCE METER

(57) Abstract

A reflectance meter for use in a blood glucose tester for measuring the colour change of test strips, treated with
blood to be tested. The reflectance meter comprises a strip gate (7) for receiving and holding a treated strip in position.
Light from a lamp source (8) is reflected from the strip and sensed by a light sensitive device (9), the output of which is
connected to an electronic measuring circuit (55) which determines blood glucose level from the intensity of reflected light
The measured level is displayed by an analogue (14), digital (43), mechanical or thermal display. The strip gates can be
coded (48) in accordance with the particular strip variety used.

FOR THE PURPOSES OF INFORMATION ONLY

Codes used to identify states party to the PCX on the front pages of pamphlets publishing international ap-
plications under the PCT.

AT

Austria

KP

Democratic People's Republic of Korea

AU

Australia

U

Liechtenstein

BE

Belgium

LK

Sri Lanka

BR

Brazil

LU

Luxembourg

cr

Central African. Republic

MC

Monaco

CG

Congo

MG

Madagascar

CH

Switzerland

MW

Malawi

CM

Cameroon

NL

Netherlands

OS

Germany, Federal Republic of

NO

Norway

DK

Denmark

BO

Romania

n

SE

Sweden

FR

France

SN

Senegal

GA

Gabon

su

Soviet Union

GB

United Kingdom

TO

Chad

HO

Hungary

TG

Togo

JP

Japan

US

United States of America

WO 83/00926 PCT/AU82/00141

- 1 -
" REFLECTANCE METER"
The present invention relates to a reflectance
meter. In particular , the invention is directed to a
reflectance meter for use in a blood glucose tester for
5 measuring the colour change of test strips treated with the
blood to be tested.

A significant proportion of the population suffer
from diabetes. Most diabetics receive a regular injection
of insulin or glucose, the frequency and dosage of the
10 injections being dependent upon the particular needs of the
patient. These requirements are determined by monitoring
the patient's blood glucose, level for an initial period of
time and .then determining future requirements by
extrapolation. However, since the blood glucose level can
15 vary widely in response to physical exercise for example ,
the extrapolated estimate may not be accurate. It is thus
highly desirable, if not necessary, to be able to obtain a
blood glucose reading when and where required.

BACKGROUND ART

20 There is known a method of determining blood glucose

level by testing the urine of a patient. The known method
involves treating a "glucose stick* with urine and
determining the blood glucose level from the change in
colour of the "glucose stick". However, such a method is
25 not only awkward but also does not provide an accurate
reading of the glucose level.

DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide
an improved reflectance meter which is accurate and
30 reliable, yet portable. Further, the apparatus of the

present invention can be manufactured inexpensively. It is
easy to operate arid practically foolproof.

According to the present invention there is
disclosed a reflectance meter for measuring the colour of a
35 strip treated with blood to be tested, the colour of said

strip being proportional to -the glucose level in said blood
sample, said reflectance meter comprising:

optical testing means, having strip receiving means,

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an optical source and a light sensitive device, said light
sensitive device being arranged to receive light from said
source after reflection from said strip positioned in said
strip receiving means;
5 electronic circuit means connected to said light

sensitive device and providing an output proportional to the
output of said light sensitive device and indicative of the
blood glucose level;

and display means connected to said electronic
10 circuit means for displaying said output*

Advantageously , the electronic circuit means
comprises a measurement circuit having a bridge circuit of
which said light sensitive device forms a part.

Preferably , the electronic circuit means also
15 comprises voltage stabilizer means for stabilizing the

voltage supplied to said measurement means, and timing means
for providing timing periods for testing said strip.

Preferably, said display means comprises a digital
numerical display, a moving coil meter or a LED display.
20 For blind operators, a mechanical display such as pop-up '
pins, or a thermal display such as an incandescent lamp
matrix, can be provided.

Preferably, said strip receiving means comprises a
hinged lid adapted to hold said strip in position by means
25 of a spring device on said lid. The strip is held in

position in the strip receiving means so that the activated
area covers an aperture or gate through which the light from
the optical source is received and reflected back to the
light sensitive device.
30 Multicoloured strips are also available

commercially. Such strips provide more criteria for judging
the colour of the treated strip. With a modification, the
present invention can also use multicoloured strips.

In this embodiment the gate is divided into more
35 than one aperture, each aperture corresponding to a
particularly coloured portion of the strip.

As strips from different manufacturers have
different characteristics, and since even strips from the

WO 83/00926

PCT/AU82/00141

same batch can vary, it is desirable to take into account
changing characteristics of different strips. To
compensate, the strip receiving means are interchangeable.
Each strip receiving means is mechanically coded so that

5 when it is inserted, the electronic circuit means will
interpret* the reflected light reading according to an
algorithm corresponding to the code of the particular strip
receiving means used. Accordingly, strips of a particular
characteristic will be used with a correspondingly coded

10 strip receiving means so that the electronic circuit means
will compensate for the particular characteristic.

The device can be used in the home and also adapted
for large scale medical or industrial use. Advantageously,
the electrical circuit of the reflectance meter is

15 simplified so that the device can be repaired by an ordinary
technician.

The invention is designed to perform the practical
functions of glucose testing required by diabetics with
little technical or medical knowledge. Although the

20 appicability of the invention is not limited to diabetics,
the device is designed particularly for use by diabetic
patients, especially young children, for obtaining a
quantitative measurement of blood glucose levels in their
blood stream. This enables the diabetic to control and

25 balance his condition, and thereby lead a near normal
lifestyle.

In testing blood glucose levels, the operator
(usually the patient himself) takes a small drop of blood
from the patient, e.g. from the tip of a finger. This blood

30 sample is then placed on the activated pad of a commerically
available reagent strip. The activated pad changes colour
in direct relation to the amount of glucose present in the
blood sample. A dark colour indicates a high glucose level
while a light colour indicates a low glucose level.

35 The blood is left on the strip for a predetermined

period of time, typically one minute. After this period of
time, excess blood is wiped or washed from the strip. The
resultant colour is measured by the reflectance meter

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according to the reflectance method, i.e. the treated
reagent strip is illuminated, and the light reflected
therefrom is monitored by a light sensitive device.

There are several systems of measurement units by

5 which the blood glucose level can be quantitatively

expressed. The display means can be calibrated for the
particular system used. In Australia, the measurement unit
used is milli-mole of glucose per litre of blood (mMol/L) .
The normal range for a diabetic is generally taken as 5 to 9

10 mMol/L with an upper limit for children set at approximately
10 mMol/L.

BRIEF DESCRIPTION OF THE DRAWINGS .
Notwithstanding any other forms that may fall within
its scope, a preferred embodiment of the present invention
15 will now be described with reference to the drawings in'
which:

Fig. 1 is an exploded schematic view of the
preferred embodiment of the present invention.

Fig. 2A is a schematic. plan view of the circuit
20 board of the embodiment of Fig. 1.

Figs 2B to 2F are schematic views of the optical
testing means of the embodiment of Fig. 1.

Fig. 3 is a circuit diagram of the electronic means
of Fig. 1.

25 Figs. 4A to 4D are schematic views of strip

receiving means according to another embodiment of the
present invention.

Figs. 5A to 5E are schematic views of strip
receiving means according to a further embodiment of the
30. present invention*

BEST MODE OF CARRYING OUT THE INVENTION
The apparatus of the preferred embodiment is housed
in a plastic case constructed in two parts, a top part 1 and
a bottom part 2. A printed circuit board 3 containing the
35 electronic circuit means, and display means such as meter 5,
are fixed to the inside of the top part 1. The bottom part
2 houses a battery pack 4 which can be an alkaline battery
or rechargeable nickel cadium battery, for example.

WO 83/00926 PCT/AU82/00141

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( The battery pack 4 is connected to the printed

circuit board 3 to power the electronic circuit means 55
which comprises (a) a control system, (b) a warning (timing)
system and (c) a measuring system. The electronic circuit
c 5 means can also be powered from a low voltage mains operated
unit which can also act as a charger unit when rechargeable
batteries are used.

The optical testing means (Figs. 2B - 2F) comprises
a plastic light chamber 7 mounted adjacent the printed
10 circuit- board 3, but preferably not rigidly connected

thereto. The light chamber 7 houses a light source such as
a precision LED 8. The light chamber 7 also contains a
light sensitive device such as a light dependent resistor
cell 9.

15 A removable strip gate 13 is fitted onto the light

chamber 7, the LDR 9 being arranged to receive light from
the precision lamp 8 after reflection from a reagent strip
inserted in the strip gate 13. Since the strip gate 13 is
removable, it may be replaced with different strip gates

20 catering for different size reagent strips.

in measuring blood glucose level, a treated test-
strip is placed into gate slot 13A of the gate 13. The
dimensions of the gate slot are such that the reagent active
pad of the test strip is positioned centrally over aperture

25 13B. Light from the precision light source 8 is projected

#

through the aperture 13B onto the "activated pad of the test
strip, and the reflected- light (which is diependent upon the
colour of the test strip) passes back through the aperture
and is received in chamber 7A. The chamber 7A contains the

30 light dependent resistor (LDR) cell 9. The resistance of
the LDR 9 varies in proportion to the intensity of light
received. The LDR 9 is used as the variable arm of a
modified Wheatstone bridge circuit 50 in the measurement
system of the electronic circuit means 55. The resultant

35 inbalance in the arms of the bridge is sensed and measured

by meter 5 f the scale of which can be calibrated to read the
appropriate units of measurement of the strip under test.
The upper and lower meter readings are standardized or

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10

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calibrated by use of a LOW reference strip (dark colour) and
a HIGH reference strip (light colour), in calibrating the
meter 5, a reference strip is inserted in the gate slot 13A
and the meter reading is adjusted to the appropriate minimum
or maximum setting by means of respective variable
potentiometers SET 1 (17) and SET 2 (18). In the described
embodiment, the zero meter reading is adjusted by SET 1
while full scale deflection is adjusted by SET 2.

It will be seen from the circuit diagram of Fig. 3
that potentiometer 17 (SET 1) is wired across the LDR
sensing cell 9 and is not in the *C n arm of the bridge
circuit as in a standard bridge circuit. In the bridge
circuit 50 of the present embodiment bridge arms B and C
also act as part of a potential divider chain when the meter
15 5 is in a stabilizer voltage measurement mode which is

selected by the N/C contacts of switch 19. When the switch
19 is pressed, the N/O contacts close, thereby placing meter
5 in a reflectance measurement mode.

By setting SET 1 and SET 2 (which typically takes
only about 10 seconds) , the system compensates for
resistance changes of LDR 9 due to temperature variations,
for example. The calibration procedure also compensates for
long term aging of the precision light source 8, and any
foreign body that may be lodged in the aperture and
25 affecting the intensity of the transmitted and/or reflected
light beams.

The bridge circuit 50, light source 8, and accurate
timer functions of the electronic circuit means are all fed
by a stabilized voltage on line 51. The stabilized voltage
30 , is monitored by the meter 5 when switch 19 is in the N/C
position, the meter deflection being adjusted by a
potentiometer 20.

The voltage stabilizer can be of the standard type
series regulator designed to maintain small differential
35 voltages. This ensures maximum battery life when dry
batteries are being used.

A warning system comprises an LED indicator 10 and a
piezo-electric buzzer 11. Also, by placing meter 5 in the

20

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WO 83/00926 PCT/AU82/00141

. -* - 7 -

voltage measurment mode, the voltage supply to electronic
circuit means can be monitored, and meter 5 indicates any
significant variation in the stabilized voltage.

Timing means providing a first short timing period

5 of approximately one minute comprises a standard type .555
timer integrated circuit 21. A switch 22 initiates the
timing cycle, and after the timing .period is completed, LED
10 turns off, thereby generating a negative pulse which is
fed via capacitance 37 to the start pin of a second 555

10 timer 23 with a time constant of approximately 3 seconds.
When the negative pulse arrives at the start pin of IC 23,
the output of IC 23 goes high and activates the
piezo-electric buzzer 11 which emits an audible tone thereby
signalling the end of the timing cycle.

15 Pressing the switch 22 also activates a further 555

IC timer 24 which is preset to approximately 5 minutes.
Timer 24 acts as an automatic cutout system, the 5 minute
period being of sufficient time in which to carry out a
single test. Preferably, the automatic turnoff functibn is

20 only operative when the device is operating from internal
batteries so that battery power is conserved. For
continuous operation, the output of the mains adaptor is
arranged to by -pass the automatic cutoff circuit via jack
socket 38.

25 A separate socket 39 is also provided so that the

mains adaptor can be used as a battery charger when,
rechargeable batteries are being used. The final charge
current can be adjusted by resistance 40.

The operation of the automatic cutoff function is as

30 follows. Operation of switch 22 connects the reed relay
coil 25 to earth or the negative rail of the supply.
Energisation of the coil 25 causes the reed contacts to
close, thereby supplying power to the voltage stabilizer
circuit. The stabilized voltage supply, which is preferably

35 4 volts, is then applied to the electronic components of the
electronic circuit means.

When the period (5 minutes) preset on timer 24 has
elapsed^ the timer 24 turns off, causing transistor 42 to

WO 83/00926

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... ■■».- - - a

turn off and relay 25 to open* The device is then
automatically turned off.

The closing of switch 22 also gates, via diode 41,
the timer IC 24 thereby causing it to commence timing* The
5 output of the timer is connected to the base of transistor
42 turning it on. The transistor 42 then maintains a
current through the relay coil 25 and holds the relay in the
closed position. A potentiometer 26 is provided in the
relay coil circuit, the coil current being variable by
10 adjustment of the variable resistor 26. The coil current
can be adjusted to allow the relay to open (thereby turning
the device off) when the battery voltage falls below a
predetermined value, typically 5.3 to 5.5 volts.

When the machine is connected to mains power via an
15 adaptor (not shown) the automatic cutoff circuit is

disconnected. The regulation of the dc supply to the
electronics is such that the ac input voltage can fall by
approximately one-third before the stabilizer voltage falls
below its critical voltage. This is unlikely to occur under
20 normal conditions.

The preferred embodiment also comprises improved
means for holding the test strip in position during
testing. A metal leaf spring 29 is provided in a gate cover
28 , the spring 29 being adjusted to place a downward
25 pressure on the test strip. This ensures that the distance
from the light source 8 to the test strip surface is held
constant and equal to the distance of the reference strips
used in the original calibration.

The gate cover 28 is preferably hinged for easy
30 cleaning of the aperture 13B. The hinge system comprises
two tabs 30 on the gate cover 28 which engage, and are
rotatable in, bearing blocks 31. It has been found that in
portable equipment of plastic construction, a hinged lid or
door is very vulnerable to„ damage if the unit is dropped.
35 In the preferred embodiment, the hinge system is such that
the bearing blocks 31 are held in slots 32. Hence, if the
lid is damaged it can be readily changed without the need to
dismantle the whole unit. Further, the lid change operation

WO 83/00926 PCT/AU82/00141

- 9 -

can be performed by the owner without any disruption to the
electronic circuit or calibration settings.

The preferred embodiment also comprises display
means for displaying the measured blood glucose level. The

5 display means is fed with output current from the electronic
circuit means and can comprise an output meter, digital
display, or bargraph using LEDs . Advantageously, the output
meter is a specially designed moving coil meter 5. The
bargraph display can comprise a series of LEDs 43, the

10 output reading being indicated by the number of LEDs which
are enabled. By using LEDs of different colours arranged in
a predetermined pattern, the output is displayed as- a
coloured band of light which has the advantage of providing
a quasi-digital display and yet giving analog information

15 using colours which are easily understood by a child. For
example, the LEDs corresponding to high levels of blood
glucose can be red LEDs while those corresponding to low
levels can be green LEDs. Thus, the operator can determine
the nature (safe or dangerous) of the blood glucose level at

20 a glance.

An analog readout i.e. moving coil meter or
bargraph, has been found to be the best form of display as
the analog system will reveal very delicate trends. For
remote country areas in Australia and especially

25 underdeveloped countries, the meter read out is preferable .
as it can be repaired easily without the need for expensive
or complex service equipment or specialized electronic
knowledge. However, as the modern preference is for digital
readouts, the bargraph or digital display can be used.

30 .At a reading of 15 mMol/L, a diabetic patient should

test for Ketones in the urine. If a bargraph display is
used, the readings above 15 mMol/L can be made to flash to
thereby remind the patient to test for Ketones. This
feature can be implemented by supplying the anodes of the

35 LEDs reading over 15 mMol/L with a pulsating dc voltage.
Oscillator IC 36 is provided for this purpose.

The analog moving coil meter can be replaced with
the bargraph display without any change to the main printed

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WO 83/00926

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circuit board 3. A printed plastic screen 15 containing the
numerical output readings corresponding to the particular
strip used, is placed in position over the LED matrix 43.
An integrated circuit 6 is used to interface the output of
5 measurement means on PC board 3 to the bargraph unit. The
integrated circuit 6 matches the balanced output of the
bridge with the unbalanced input of the bargraph, which
comprises comparator integrated circuits 35. The output
from the comparators 35 is connected to a LED indicator
10 matrix 43, which is typically a 4X5 matrix.

The LEDs will light up in proportionate number to
the colour of the strip being tested. The comparators 35
are operated in a linear mode, but the colour change of the
test strip is non-linear. In order to compensate for this
15 aspect, the input to output characteristic of integrated

circuit 6 is made non-linear and matched to the subject test
strip by means of a feedback resistor network 16. The
resistor network 16 is a plug in unit and can be changed to
suit the colour proportionality law of different strips.
20 In calibrating the bargraph display, SET 1 and SET 2

are adjusted by the respective potentiometer to just light
up the first and last LED.

For blind operators, a mechanical or thermal display
can be used. The mechanical display is analogous to the
25 bargraph display except that the LEDs. are replaced by pins

which n pop up w on energization. The blind operator cam then
"read? the pin display by touch. In an alternative thermal
display, the LEDs are replaced by incandescant lamps. The
operator can then "read" the display by sensing the heat
30 radiated by the enabled lamps.

High accuracy in blood glucose readings can be
achieved if there are more criteria for judging the colour
of the treated strip. For example, the effect of the blood
stain on a light strip and a dajrk strip can be compared to
35 pin point the glucose level more accurately.

Another embodiment of the present invention,
illustrated in Fig. 4, utilizes the effect of a blood stain
on different coloured strips. In this embodiment, a

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modified strip gate 48 is provided in wbich the aperture 49
is divided into two. The gate is designed to be used with
commercially available strips of two colours so that when
the strip is inserted into the gate, two treated portions of
5 different colours 45, 46 will be positioned respectively

across two apertures. This is achieved by ensuring that the
divider line 47 (which divides the total aperture 49 into
the two apertures) covers the boundary line between the two
coloured portions of the strip. *An eccentric adjustable

10 strip stop 44 is provided to ensure that the treated section
is properly positioned with respect to the light source, and
that the boundary of the two coloured sections coincides
with the dividing line 47.

Strips sold by different manufacturers, and even

15 from the same manufacturer, come in different varieties,

each having peculiar characteristics. If different strips
are used, the electronic means must compensate for the
different characteristics. In a further embodiment of the
present invention, illustrated in Fig. 5,. coded

20 interchangeable strip gates 60 are provided, the gate code
indicating the particular strip being used. The gate is
physically coded by notches €l at predetermined distances
across the front of the gate as shown in Fig. 5E. A code
reader is shown in Figs. 5B - 5D and comprises a horizontal

25 contact bar 62 and a plurality of vertical contact rods 63.
When the gate 60 is inserted, the rods 63 Will be bent out
of contact with the bar 62, except for those rods
corresponding to notches 61 in the gate. Thus, by sensing
which rods are still in electrical contact with the bar 62,

30 the code is decoded and the electronic circuit means

automatically compensates for the particular strip used.

The foregoing describes only some embodiments of the
present invention and modifications, obvious to those
skilled in the art, made be made thereto without departing

35 from the scope of the invention as claimed hereafter. For
example, the reflectance meter can be used for strips
treated with other liquids, e.g. urine.

OMPI

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" - - - " - 12 -

1 a •„ CLAIMS

reflectance meter for „o„ ,-

reflectance „eter con,prisi„ 9 . * Sample ' "«

receive U9 bt fro* said scarce after rltl to

po^cea In saia strlp r:::^ 1 ::::; frM saia

« the „asurea oiooa giuccse le«l! * * indlcatl "

' -herein sua electroST ^ " *-.««. 1

strip gate ^.zTzzr^t™ a re ~*
-a, and Mans for readlng iztTi^^r*

inserted into sua *eter. 9 " e 15

wherein sua sLTS^f" 35 Claimea in Clai »
Plurality of apertures leia "! 3 ""^ «

co„ unioate * '« apertu " s ""in, positioned to

«~^:^^^^ - *

Preceding'clai* STTLT* " * My

dai»s it , i"r:ra^r:: iaiMd in any

actnatea aispia^a SEa^E*

WO 83/00926

PCT/AU82/00141

...... — - - 13 -

7. A reflectance meter as claimed in any
preceding claim wherein said electronic circuit means
comprises timing means for issuing timing signals for the
blood test.

8. A reflectance meter as claimed in any
preceding claim wherein said electronic circuit means
comprises a voltage stablizing circuit for regulating the
voltage thereto,

9. A reflectance meter as claimed in any
preceding claim , wherein said optical testing means further
comprises an adjustable stop for an inserted strip.

WO 83/00926 . $ : PCT/AU82/00141 "

INTERNATIONAL SEARCH REPORT

International Application No PCT/AU82/00141

I. CLASSIFICATION OF SUBJECT MATTER (H several dasablcstlon symbol* apply. Indicate all) »

According to International Patent Classification (IPC) or to both National Classification and IPC

Int. CP G01N 21/01 , 21/27; GOU 3/46

IL FIELDS SEARCHED

Minimum Documentation Searched *

Classification System

Classification Symbols

IPC

G01N 21/01, 21/27, 33/16, 33/48, 33/52, 33/66; G01 J 3/46

Documentation Searched other than Minimum Documentation
to the Extent that such Documents are Included In the Fields Searched *

AU: IPC as above; Australian Classification 00.4

IIL DOCUMENTS CONSIDERED TO BE RELEVANT *«

Category *

Citation of Document. *« with Indication, where appropriate, of the relevant passages '

US,A, 3604815 (MILES LABORATORIES, INC) 14 September
1971 (14.09.71)" See particularly column 7, lines
18-48, column 6, lines 39-44 and column 5, lines 31-
44 & De, A 1920404.

DE,A, 3026439 (SIGMA INSTRUMENTE GmbH) 11 February
1982, (11.02.82) ■

Rel»vant to Claim No. «

(1,2,5-9)

0.)

• Special categories of cited documents: **

"A* document defining the general state of the art which Is not

considered to be of particular relevance
T earlier document but published on or after the International

filing date

"L" document wWch may throw doubts on priority claJm(s) or
which Is cited to establish the publication date of another
citation or other special reason (as specified)

-O" document referring to an oral disclosure, use, exhibition or
other means

•P- document published prior to the international fifing date but
later than the priority date claimed

later document published aft er Jhe International fUlng date
or priority date and not In conflict with the appBcatton but
cited to understand the principle or theory underlying the
Invention

document of particular relevance; the claimed Invention
cannot be considered novel or cannot be considered to
Involve en Inventive step

document of particular relevance: the- claimed Inversion
cannot be considered to involve an inventive step when tne
document is combined wHh one or more other such docu-
ments, such combination being obvious to a person swiied
in the art.

document member of the same patent family

IV. CERTIFICATION

Date of the Actual Completion of the international Search *

10 November, 1982 (10.11,82)

Date of MaiSno of this International Search Report «

International Searching Authority 1

Australian Patent Office.

Signature of Airtfcorixed Officer *°

R.E.W. HAY • >

Form PCT/1SA/210 (second sheet) (October 15S1)

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